The chemical plant was originally established as a milling plant for barite from the Mont’Ega mine in Narcao.
The company operated to prospect for argentiferous lead and barite, and from Mont’Ega it obtained barium salts for industrial uses. The new Company therefore was interested in the exploitation of barite, for which a grinding mill was installed at the town of San Giovanni Suergiu, adjacent to the area that would house the railway station from 1926. Administrative buildings, workers’ houses and an infirmary were built there. The entire area was subjected to reclamation with the assistance of the state. The entire complex, now owned by the Lower Sulcis Land Reclamation Consortium, is clearly visible from State Highway 195 at the entrance to the town.
The plant facility was built by the German firm Humbolt, and annual production was 2,000 tons, half of which was sold domestically, the rest to England, the British and Dutch Indies, and North America. In 1935 30 workers were employed, and in 1937 the Compagnia Chimico Mineraria merged with the Società Magnesio Italiano del Sulcis, taking the name S.A.M.I.S.; in that same 1937 the Company, not having received ministerial authorization for the production of lithopone, directed its industrial activity toward the production of magnesium metal and the distillation of Sulcis coal. A sudden drop in magnesium metal production in 1938 led to the plant’s cessation of operations in 1939. All the mechanical equipment was allocated to other mining plants with the exception of the distillation sector, which was acquired by ACal, which had meanwhile begun construction of its distillation plant at S. Antioco Ponti. The new plant was to produce mainly gasoline from the distillation of Sulcis Coal and other by-products such as lubricating oils and naphtha. The San Giovanni Suergiu plant was purchased by Carbosarda in 1942 and continued barite production until 1948. The last concessionaire, the Possis Mining Company assigned the plant to the production of bentonite, for the treatment of which the settling tanks, still visible today, were built. The industrial complex became the property of the Reclamation Consortium, while the buildings were acquired by the Municipality of San Giovanni Suergiu.
